Rapid Methods for the Extraction of Nucleic Acids from Biological Samples

ABSTRACT

The invention is directed to compositions and methods for rapidly and efficiently extracting nucleic acids and/or targeted nucleic acids sequences from biological samples. The methods of the invention comprise combining the sample with a buffer and magnetic silicon beads and concentrating the beads with a magnet or other electrical field. Liquid may be removed, or not, and an alkaline buffer is added followed by magnetic carboxy beads in a binding buffer so that nucleic acids transfer to the carboxy beads, which can be easily and quickly isolated once again with a magnet. Total nucleic acid extraction is greatly enhanced. Extracted nucleic acids can be analyzed, for example, by PCR wherein the nucleic acids can be identified and characterized. Carboxy beads may also contain a ligand so as to target specific nucleic acid sequences. The invention is also directed to kits comprising the tools and compositions for performing the methods of the invention.

REFERENCE TO RELATED APPLICATIONS

This Application is a continuation of U.S. application Ser. No.15/152,871 filed May 12, 2016, which issued as U.S. Pat. No. 9,976,136on May 22, 2018, which claims priority to U.S. Provisional ApplicationNo. 62/232,666 filed Sep. 25, 2015, and U.S. Provisional Application No.62/161,527 filed May 14, 2015, the entirety of each of which isspecifically incorporated herein.

FIELD OF THE INVENTION

The invention is directed to rapid methods for the extraction of totaland/or targeted nucleic acids from a biological sample and, inparticular, to tools, methods and compositions containing componentsthat facilitate concentration and isolation/extraction of nucleic acidsfrom samples.

BACKGROUND OF THE INVENTION

The ability to maintain the integrity of nucleic acids in a biologicalsample (and in particular, those contained in diagnostic samplesobtained from human patients), whether the specimen is taken in a remotefield location, a doctor's office or in a laboratory, often determineswhether the nucleic acids can be successfully analyzed. Typically,nucleic acids in a biological sample will quickly degrade and/ordenature at ambient temperatures. This problem is magnified when aspecimen is collected at a remote field site, or a significant distancefrom a doctor's office or laboratory environment, and especially wherethere may be limited or no access to refrigerator/freezer conditions.Problems associated with the collection and handling of biologicalspecimens are further exacerbated when the desired nucleic acids fordownstream analysis include ribonucleic acid (RNA), which isparticularly susceptible to degradation by endogenous or exogenousnuclease activity.

Another concern when working with biological specimens is the risk ofrelease of infectious agents to individuals and the environment and, inaddition, contamination to the biological specimen itself. This isespecially true with regard to the handling of potentially infectiousbiological agents such as Ebola, avian influenza, severe acuterespiratory syndrome (SARS), and many others.

Molecular diagnostics has changed drastically with the advent ofpolymerase chain reaction (PCR) and thereafter with real-time PCR.Nucleic-acid based detection platforms employing e.g., quantitativereal-time PCR (qPCR) or reverse transcriptase PCR (RT-PCR) andquantitative, real-time, reverse transcriptase PCR (qRT-PCR) assays candeliver results in hours versus days required for traditional cultureand isolation methods making molecular detection methods the mainstay ofmodern diagnostic laboratory analysis.

Several commercial companies (e.g., Qiagen [Valencia, Calif., USA],Roche Applied Science [Indianapolis, Ind., USA], Gen-Probe [San Diego,Calif., USA], and bioMérieux [Durham, N.C., USA]) have developedinstruments to automate the nucleic acid extraction process from sampleisolation to molecular analysis. For example, the Tigris DTS®(Gen-Probe, San Diego, Calif., USA) automates the entire detectionprocess, and in late 2004 was approved by the U.S. Food and DrugAdministration (FDA) for simultaneously detecting Chlamydia trachomatisand Neisseria gonorrhoeae using Gen-Probe's APTIMA COMBO-2® amplifiednucleic acid test (NAT) assay.

In view of the requirement for high-quality nucleic acid samples incontemporary detection and assay systems, there is a need in the art forsafe and facile collection and analysis of high-quality quality nucleicacids contained within a variety of biological samples and specimens.There is also a need for high efficiency in the collection of nucleicacids. For nucleic acid testing, the issue is not always the absoluteamount of the sample collected, but the amount of nucleic acid recoveredfrom the sample. Inefficient recovery of nucleic acids requires repeatedcollection efforts, which are not always possible. There is also a needfor more rapid collection efforts that can be automated for efficienthigh-throughput methods to recover the highest percentage of nucleicacids possible from the biological sample collected, so that samples canbe appropriately and rapidly analyzed for a variety of nucleic acidsincluding RNA and DNA, genes, genomes and specific sequences.

SUMMARY OF THE INVENTION

The present invention encompasses new and useful tools, compositions,and methods of rapidly and efficiently collecting and identifying genesand nucleic acids of interest from a biological sample.

One embodiment of the invention is directed to methods of extractingnucleic acids from a biological sample containing cells and/ormicroorganisms comprising: adding a matrix material and a buffer to thebiological sample, wherein the matrix material binds to the nucleicacids of the sample; isolating matrix material bound to nucleic acids ofthe sample; adding an intermediate buffer that promotes a release ofnucleic acids to form a mixture, adding another magnetic matrix materialand a binding buffer to the mixture wherein the magnetic matrix materialpossess a chemical modification that binds nucleic acids, preferably aspecific nucleic acid sequence; exposing the mixture to a magnetic fieldto concentrate the magnetic matrix material bound to the nucleic acids;adding an extraction buffer to the concentrated magnetic matrix materialwherein the nucleic acids are extracted from the magnetic matrixmaterial. Preferably the biological sample comprises human, animal,microbial or plant material and also preferably, the nucleic acids ofinterest comprise a nucleic acid sequence such as, for example, a cancermarker sequence, cancer marker sequences, sequences indicating thepresence of a pathogenic organism or infection, sequences indicating aphenotypic condition of an organism, sequencing indicating a lineage,sequences indicating identifiable characteristics, sequences indicatinga mutation, sequences indicating a change from a wild-type or otherknown sequence, or a combination thereof. Preferred are nucleic acids ofinterest that are specific to a pathogen such as, for example, a virus,a bacterium, a parasite, a fungus or a combination thereof. In apreferred embodiment, the matrix material comprises magnetic beads ofsilicone, porcelain, ceramic, plastic, glass or polymer. The matrixmaterial used may or may not disrupt the cells and/or microorganisms ofthe biological sample. When the cells/microorganisms are disrupted, thematrix materials bind to nucleic acids released from the disrupted cellsand/or microorganisms. When the cells/microorganisms are not disrupted,the matrix materials bind to extracellular nucleic acids. Preferably,the buffer lyses cells, inactivates nucleases, sterilizes the sample andmaintains the integrity of the nucleic acids. Preferred this buffercontains at least a chaotrope, a detergent, a reducing agent and achelator at a pH of about 6-8. Alternatively, the buffer may maintainthe integrity of cells of the sample and not lyse cells, which is usefulfor analysis of only excreted nucleic acids and suspended molecules whencells lysis is not desired. Preferably the intermediate buffer causesthe release of nucleic acid from the first matrix material and promotesbinding to the second matrix material. Also preferably, the intermediatebuffer comprises TE, saline, an alkaline solution, NALC(N-acetyl-L-cysteine-sodium citrate-NaOH) or a combination thereof.Preferably the binding buffer contain PEG, a salt such as NaCl, achelator such as EDTA, a detergent such as Tween-20 and/or Triton X100,a buffering agent such as Tris-HCl, and an alcohol such as ethanol.Preferably, the extraction buffer may comprise a PEG/salt buffer whereinthe chemical modification promotes release of the nucleic acids from themagnetic matrix material. Preferably the magnetic field or the anothermagnetic field is an electro-magnetic field and the extracted nucleicacids are identifiable by molecular analysis such as, for example, PCRwhich does not involve centrifugation or additional nucleic acidpurification. Also preferably, the method is automated forhigh-throughput analysis of a plurality of biological samples sequencesof the extracted nucleic acid can be identified by molecular analysissuch as, for example, PCR (polymerase chain reaction). Preferablyextraction efficiency, as measured by PCR cycle threshold, is lower ascompared with extraction efficiency for a conventional extractionprocedure such as, for example, a silica spin column extraction.

Another embodiment of the invention comprises methods of extractingnucleic acids from a biological sample comprising: concentrating nucleicacids of a biological sample; adding an intermediate buffer that isalkaline and magnetic beads in an aqueous or binding buffer comprisingPEG to the concentrated nucleic acids to form a mixture, wherein thebeads bind to nucleic acids; exposing the mixture to a magnetic fieldthat concentrates the bound magnetic beads and removing the buffer;adding an extraction buffer to the concentrated beads wherein thenucleic acids separate from the magnetic beads; and exposing the mixtureto another magnetic field to remove the magnetic beads and isolate thenucleic acids. Preferably concentrating comprises adding magnetic beadsand a buffer to the biological sample, wherein the buffer comprises achaotrope, a detergent, a reducing agent, and a chelator at a pH ofabout 6-8, removing the magnetic beads, and adding an intermediatebuffer suspending the magnetic beads in an. Also preferably analyzingthe isolated nucleic acids is by a PCR that does not involvecentrifugation or additional nucleic acid purification which is all beautomated for high-throughput analysis of a plurality of biologicalsamples. Preferably extraction efficiency, as measured by PCR cyclethreshold, is lower as compared with extraction efficiency for aconventional extraction procedure wherein the conventional extractionprocedure is a silica spin column extraction.

Another embodiment of the invention comprises kits comprising: asolution that contains a matrix material and a buffer; an intermediatebuffer with a pH above 7 and preferably 8 or above or 9 or above; andmagnetic carboxy beads in a binding buffer. Preferably the first bufferis a lysis buffer that lyses cell walls, sterilizes the sample, andmaintains the integrity of nucleic acids. Alternatively, the buffer maybe a non-lysis buffer that maintains the integrity of cell walls wherecell lysis would not be desired. Preferred lysis buffer contains achaotrope, a detergent, a reducing agent and a chelator at a pH of about6-8. Preferably the matrix material comprises silica dioxide beads, thelysis solution lyses cells, inactivates nucleases and sterilizes abiological sample. Preferably the intermediate buffer comprises a highpH buffer such as pH 8 or above, or pH 9 or above, or pH 10 or above.Preferably the binding buffer is aqueous and comprises one or more ofPEG, a salt, a chelator, a detergent and/or an alcohol. Also preferably,kits may further comprise a magnet or electromagnet.

Other embodiments and advantages of the invention are set forth in partin the description, which follows, and in part, may be obvious from thisdescription, or may be learned from the practice of the invention.

DESCRIPTION OF THE FIGURES

FIG. 1 Concentrating nucleic acids using magnetized silica beds andPrimeStore MTM™.

FIG. 2 Extraction using a concentration step with beads in PrimeStore™from low-level MTB sample at 10¹ CFU/ml.

FIG. 3 Concentrating nucleic acids directly from PrimeStore MTM™ tubescontaining magnetic silica beads.

FIG. 4 MTB nucleic acid purification using magnetic beads in bufferformulations compared to AgenCourt buffer/beads.

FIG. 5 Extraction with carboxylated magnetic beads in comparison withextraction from silica spin columns.

FIG. 6 Adenovirus detection using bead extraction method compared tospin column extraction.

FIG. 7 Detection of Adenovirus using different types of carboxy beads.

FIG. 8 Ten-fold serial reduction of glutaraldehyde fixed wholeMycobacterium tuberculosis (MTB) detection using real-time PrimeMix MTBMultiplex assay.

FIG. 9 MTB detection post 1.0 ml concentration using spin-column andbead-based extraction.

FIG. 10 Real-time PCT detection of MTB.

FIG. 11. Summary of bead extract method.

FIG. 12. (A-C) qPCR cycle threshold (C_(T)) detectiuon values fromRNA/DNA extracted using Qiagen DNA mini vs. Longhorn beads from: (FIG.12A) influenza A virus; (FIG. 12B) adenovirus; and (FIG. 12C) M.tuberculosis from 10-fold dilutions in Primestore MTM. A C_(T) value of40 indicates not detected.

FIG. 13. (A-C) RNA/DNA qPCR efficiency from Qiagen DNA mini vs. Longhornbead extractions using a 10-fold serial dilution of: (FIG. 13A)influenza A virus; (FIG. 13B) adenovirus; and (FIG. 13C) M. tuberculosisin PS-MTM.

DESCRIPTION OF THE INVENTION

Extended stabilization, collection, transport, preservation andisolation compositions are in great demand as the ability to screenlarge populations for diseases and disorders is increasing. Samples orspecimens are often located in geographical regions that are remote froma testing facility. As new tools and procedures are developed toincrease the speed of nucleic acid recovery, there is a typical loss inthe recovery efficiency. High throughput screening results in a loss ofthe amount and/or quality of nucleic acids recovered from individualsamples which compromises subsequent nucleic acid testing.

Molecular diagnosis such as real-time PCR (qPCR) and next-generationsequencing (NGS) continue to improve early detection of infectiousdisease. Detection is limited by the initial quality and concentrationof nucleic acids (RNA/DNA) collected from specimens. PrimeStore MTM(PS-MTM) is a specimen collection and transport medium that killsmicrobes and preserves nucleic acids at elevated temperatures tomaintain high quality RNA/DNA for PCR and NGS. PS-MTM is compatible withmost nucleic acid extraction methods including Qiagen silica spincolumns and bead-based automated extraction platforms.

It has been surprisingly discovered that desired nucleic acids andpreferably nucleic acids can be obtained efficiently and in greateramounts than otherwise available from conventional procedures bycollecting the biological sample with affinity chromatography matrixmaterials according to the compositions and/or methods of the invention.These compositions and methods maximize the amount of nucleic acidsextracted from biological sample, while preserving and maintaining bothhigh quality and high fidelity (e.g., sequence fidelity of nucleotides,deoxynucleotides, ribonucleotides, sequences, genes or genomes). Usingthe procedures of the invention, nucleic acids are rapidly extractedwithout any need for traditional isolation tools such as spin columns.In addition, the procedures of the invention can be performed in asingle vessel and these procedures lend themselves to automation. Also,nucleic acids are spared the deleterious effects routinely observed inconventional samples that are subjected to degradation and contaminationduring the multiple steps involved with the collection, isolation,storage, and transport processes with a loss overall recovery.

Nucleic acids that can be extracted from biological samples by thecompositions and methods of the invention include, but are not limitedto all forms of DNA and RNA including but not limited to rRNA, mtDNA,siRNA, ss and ds nucleic acids, extra-cellular DNA and/or RNA, CAN, andartificial nucleotides that may be present. Nucleic acid sequences thatcan be detected and/or identified include, but are not limited to genes,genomes, cancer marker sequences, sequences indicating the presence of apathogenic organism or infection, sequences indicating a phenotypiccondition of an organism, sequencing indicating a lineage, sequencesindicating identifiable characteristics, sequences indicating amutation, sequences indicating a change from a wild-type or other knowsequence, or a combination thereof. In addition, the compositions andmethods of the invention are amenable to automation for accuratehigh-throughput analysis.

One embodiment of the invention is directed to methods of extractingnucleic acids from a biological sample. Preferred methods involvedconcentrating the nucleic acids from the biological sample by adding tothe biological sample a matrix material and a buffer. Preferably thebuffer is a lysis buffer that lyses cells, inactivates nucleases,stabilizes one or more of the macromolecules of the sample such as thenucleic acids, and sterilizes the sample, wherein the matrix materialsbinds to the nucleic acids. Alternatively, the buffer may be a non-lysisbuffer that supports cell integrity such that the matrix material bindsto extracellular nucleic acids. Bound matrix materials can be isolatedand combined with an intermediate buffer forming a mixture that causesthe matric material to release the nucleic acids into solution.Additional magnetic beads in an aqueous buffer are added to the mixture,wherein the additional beads possess a chemical modification that bindsto the nucleic acids of interest (e.g., a specific sequence or specificstructure of interest which may be specific to a pathogenicmicroorganism or a disorder) that have released from the first matrixmaterial. The mixture is exposed to a magnetic field to concentrate themagnetic beads bound to the nucleic acids of interest. An extractionbuffer is added to the concentrated beads wherein the nucleic acids ofinterest separate from the magnetic beads. Exposing the mixture toanother magnetic field allows for separation and/or removal of themagnetic beads from the liquid and isolation of the extracted nucleicacids. Using the methods of the invention, as compared to conventionalprocedures such as silica spin column extraction, extraction efficiencyof nucleic acids of interest is increased at least 5% or more,preferably 10% or more, and more preferably 15% or more, more preferably20% or more, more preferably 40% or more, more preferably 50% or more,and more preferably 75% or more. This increased efficiency can be thedifference between samples being useful and wasted samples. Wastedsamples may require repeated collection, although repeated collection isoften not possible.

Preferably the extraction of nucleic acids from biological specimenssuch that living material contained therein is killed or otherwiserendered harmless to pose no or minimal risk of exposure, while at thesame time nucleic acids are released for analysis from membranes andother structures that otherwise require additional steps. Compositionsto concentrate nucleic acids destroy or render sufficiently inactiveenzymes that may be present in the sample that often degrade nucleicacids. Compositions also facilitate the release of DNA/RNA from cells,cell membranes, sub-cellular structures and/or other structures presentin the sample. Preferably, the released nucleic acids bind to adetectable affinity matrix material, also a preferred component of thecomposition, for ease of isolation and/or analysis of the nucleic acids.Preferably, the composition and the sample are maintained in a singlereaction vessel, such that the integrity of the nucleic acids to bedetected is at least sufficiently maintained for later diagnosticanalysis. Thus, in one-step, the composition of the inventionsimultaneously: inactivates or kills pathogens that may be present inthe sample; inhibits or prevents enzymatic degradation of nucleic acidsof the sample that are targeted for later identification, facilitatesthe release of target nucleic acids from cells and cell structurespresent in the sample, facilitates separation of released nucleic acidsand maintains the integrity of the nucleic acids for later analysis.Preferably, the composition containing the sample does not requirerefrigeration or freezing and, more preferably, can be maintained atambient temperatures throughout the sample collection process and at alltimes prior to analysis. Optionally, the composition may containpredetermined nucleic acid sequences that can serve as one or moreinternal positive controls (IPC) or one or more internal negativecontrols (INC) to monitor fidelity, accuracy and/or obtain qualitativeand/or quantitative information from the subsequent analysis. Alsooptionally, compositions may contain carrier nucleic acid such as DNA orRNA.

The ability to achieve all of these desirable functions in a single-stepformulation, preferably in a single reaction zone or reaction vessel, isa particularly marked advantage over that presently available.Presently, existing technologies do not include a single-stepcomposition and/or a single vessel system that provides for inactivationof biological components containing nucleic acids, release of thenucleic acids through chemical and/or physical lysis of cells followedby separation or release of RNA/DNA, maintenance of the integrity of theliberated population of nucleic acids, facilitate the isolation of thedesired nucleic acids for later analysis, and IPCs and/or INCs tofurther quantify nucleic acids in the sample. The present invention bothstabilizes and preserves the integrity of the nucleic acids from thesample for diagnostic testing, while also providing convenient tools forisolating, concentrating and monitoring, and analyzing total nucleicacids, and/or targeted nucleic acids within the sample. Thus, thecompositions and methods of the invention are ideal for clinical, fieldand deployment use, or for high volume sample collection and extractionprocedures. Biological samples collected in compositions of theinvention are biologically inactivated, and therefore, may be safelyshipped and stored, typically without refrigeration or freezing.

Nucleic acids of the sample that can be detected include, but are notlimited to nucleic acids such as DNA and RNA (including for exampleintracellular or extracellular DNA and/or RNA) or any identifiablesequences therein. Preferably, the nucleic acids to be detected in thecollected samples are nucleic acid from a conserved sequence that isindicative of an infection or disorder, or for screening purposes.Nucleic acids of biological samples are typically located within cells,but are also found circulating freely in fluids such as blood andinterstitial fluid. These DNA and RNA molecules may be derived fromdying cells that break down and release their contents into the bloodstream, and are often referred to as circulating nucleic acids (CNA).Detection of specific CNA sequences can be advantageous fordetermination and identification of a disease or disorder in anindividual such as, for example, in acute medicine, diabetes, oncologyand fetal medicine to name a few.

The first buffers of the invention preferably contain: a) one or morechaotropes (preferably present in the composition an amount from about0.5 M to about 6 M); b) one or more detergents (preferably present inthe composition an amount from about 0.1% to about 1%); c) one or morechelators (preferably present in the composition in an amount from about0.01 mM to about 1 mM); d) one or more reducing agents (preferablypresent in the composition in an amount from about 0.001 M to about 0.3M); e) one or more defoaming agents (preferably present in thecomposition in an amount from about 0.0001% to about 0.3%); and (f) oneor more matrix materials and preferably affinity chromatography matrixmaterial, and preferably present in the compositions in an effectiveamount that facilitates extraction and isolation of a diagnostic nucleicacid. Preferred amounts are from about 1 ng to 10 μg per 100 μl.

Exemplary chaotropes include, preferably, guanidine thiocyanate (GuSCN),guanidine hydrochloride (GuHCl), guanidine isothionate, potassiumthiocyanate (KSCN), sodium iodide, sodium perchlorate, urea, or anycombination thereof. Descriptions of additional exemplary chaotropes andchaotropic salts can be found in U.S. Pat. No. 5,234,809 entitled“Process for Isolating Nucleic Acid,” which issued Aug. 10, 1993(specifically incorporated herein in its entirety by express referencethereto).

Exemplary detergents include, preferably, sodium dodecyl sulfate (SDS),lithium dodecyl sulfate (LDS), sodium taurodeoxycholate (NaTDC), sodiumtaurocholate (NaTC), sodium glycocholate (NaGC), sodium deoxycholate(NaDC), sodium cholate, sodium alkylbenzene sulfonate (NaABS), N-lauroylsarcosine (NLS), salts of carboxylic acids (i.e., soaps), salts ofsulfonic acids, salts of sulfuric acid, phosphoric and polyphosphoricacid esters, alkylphosphates, monoalkyl phosphate (MAP), and salts ofperfluorocarboxylic acids, anionic detergents including those describedin U.S. Pat. No. 5,691,299 (specifically incorporated herein in itsentirety by express reference thereto), or any combination thereof.

Exemplary reducing agents include, preferably, 2-mercaptoethanol (β-ME),tris(2-carboxyethyl)phosphine (TCEP), dithiothreitol (DTT), formamide,dimethylsulfoxide (DMSO), or any combination thereof. In a preferredembodiment, the reducing agent includes or is TCEP.

Exemplary chelators include, preferably, ethylene glycol tetraaceticacid (EGTA), hydroxyethylethylenediaminetriacetic acid (HEDTA),diethylene triamine pentaacetic acid (DTPA),N,N-bis(carboxymethyl)glycine (NTA), ethylenediaminetetraacetic (EDTA),citrate anhydrous, sodium citrate, calcium citrate, ammonium citrate,ammonium bicitrate, citric acid, diammonium citrate, potassium citrate,magnesium citrate, ferric ammonium citrate, lithium citrate, or anycombination thereof. In preferred embodiments, the chelator includesEDTA, a citrate, or a combination thereof. In a more preferredembodiment, the chelator includes EDT.

The compositions of the invention can further include a defoaming agentto prevent the formation of bubbles that typically result from thepresence of detergents in the formulation. Defoaming agents facilitatepipetting and handling of the disclosed compositions. Exemplarysurfactants/defoaming agents include, preferably, cocoamidopropylhydroxysultaine, alkylaminopropionic acids, imidazoline carboxylates,betaines, sulfobetaines, sultaines, alkylphenol ethoxylates, alcoholethoxylates, polyoxyethylenated polyoxypropylene glycols,polyoxyethylenated mercaptans, long-chain carboxylic acid esters,alkonolamides, tertiary acetylenic glycols, polyoxyethylenatedsilicones, N-alkylpyrrolidones, alkylpolyglycosidases, silicone polymerssuch as Antifoam A®, or polysorbates such as Tween®, or any combinationthereof. In a preferred embodiment, a defoaming agent includes asilicone polymer.

Exemplary nucleic acid capture matrix (NACM) materials include,preferably, agarose, glass, cellulose, polyacrylamide, Sepharose,Sephadex, silica, or another matrix media. Preferably, the NACM materialis coated with a nucleic acid binding substance (NABS), such as, forexample, nucleic acid (NA) binding proteins, antibodies and chemicalswith an affinity for NAs including single-stranded nucleic acidsequences. NACM include materials coupled to specific antibodies orantibody fragments or other nucleic acids or ligands that facilitateextract and/or isolation of the diagnostic molecule of interest.Affinity beads are preferably magnetic beads such as, for example, beadscommercially available from Dynabeads®, Life Technologies; TurboBeads,TurboBeads Inc. or PureProteome™, and Millipore. Beads may contain poresof defined sizes that are useful for inclusion or exclusion molecularsize chromatography. NACM materials includes matrix media such as, forexample, resins that are useful with the compositions and method of theinvention such as, preferably, amino acid resins, carbohydrate resins,ion exchange resins, and hydrophobic and hydrophilic resins. Thepresence of matrix material in the composition of the invention serve tofacilitate the release and subsequent capture of nucleic acids from thecells, cell structures, nucleic acids, and biological and non-biologicaldebris of the sample. Preferably, these same matrix materials can thenserve to expedite the isolation of the nucleic acids for later analysisthrough magnetic attraction (e.g., magnetic field, electro-magneticfield, magnet), molecular affinity, ionic or non-ionic interactions,density or specific density, hydrophobic or hydrophilic interactions,shape, color or light emission or absorption or any unique oridentifiable distinguishing chemical or physical property.

Buffers of the invention include one or more compounds (each preferablypresent in the final composition in an amount from about 1 mM to about 1M). Exemplary buffers include, preferably,tris(hydroxymethyl)aminomethane (Tris), citrate,2-(N-morpholino)ethanesulfonic acid (MES),N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES),1,3-bis(tris(hydroxymethyl)methylamino)propane (Bis-Tris),3-(cyclohexylamino)-1-propanesuhinic acid (CAPS),3-(cyclohexylamino)-2-hydroxy-1-propanesuhicic acid (CAPS 0),4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES),3-(N-morpholino)propane sulfonic acid (MOPS),3-(N-morpholino)-2-hydroxypropanesulfonic acid (MOPSO),piperazine-N,N\′-bis(2-hydroxypropanesulfonic acid (POPS 0),N-[Tris(hydroxymethyl)methyl]-3-amino propane sulfonic acid (TAPS),N-[Tris(hydroxymethyl)methyl]-3-amino-2-hyidroxypropansulfonic acid(TAPSO), N-[Tris(hydroxymethyl)methyl]-2-aminoethanesulfonic acid (TES),N,N-bis(2-hydroxyethyl)glycine (Bicine),N-[tris(hydroxymethyl)methyl]glycine (Tricine),N-2-acetamido-2-iminodiacetic acid (ADA),N-(2-acetamido)-2-aminoethanesulfonic acid (ACES),piperazine-1,4-bis(2-ethanesulfonic acid) (PIPES), bicarbonate,phosphate, or any combination thereof. In a preferred embodiment, thebuffer includes a citrate.

The inclusion of one or more of such optional but preferred buffers isdesirable to control the pH of the formulations, since it has been foundthat nucleic acid extraction is optimal in a pH range of about 5 to 8.Preferably, the one or more buffers employed in the disclosedcompositions are chosen to provide a significant buffering capacity inthe range from a pH of about 5.5 to about 7.5, more preferably within apH range of about 6 to about 7, and more preferably still, within a pHrange of about 6.2 to about 6.8. In exemplary embodiments, the pH of aPrimeStore™ solution (also referred to herein as “PSS”) is preferablyabout 6.9±0.25.

The compositions of the invention may also further optionally includeone or more short-chain (preferably from 1- to 6-carbon [i.e., C₁-C₆]alcohols) alkanols (each preferably present in the composition in anamount from about 1% to about 25%, although higher percentages of thealcohols may be employed if desired). Exemplary short-chain alkanolsinclude linear and branched-chain alcohols, such as, without limitation,methanol, ethanol, propanol, butanol, pentanol, hexanol, or anycombination thereof.

The compositions of the invention may also further optionally includeone or more additional compounds or reagents including, withoutlimitation, cationic functionalized zwitterionic compounds such asbetaines (including, without limitation, N,N,N-trimethylglycine,cocamidopropyl betaine, and the like), albuminoids (including, withoutlimitation, ovalbumin, and the serum albumins of bovine, equine, orhuman origin), and osmolytes (including, without limitation,trimethylamine N-oxide (TMAO), dimethylsulfoniopropionate, sarcosine,and saccharides or sugar alcohols including, without limitation,trehalose, maltose, rhamnose, sucrose, arabinose, fucose, mannitol,sorbitol, adonitol, and the like).

Preferably, the compositions of the invention provide sufficientbuffering capacity to adequately stabilize the populations ofpolynucleotides obtained from a sample, and will, most preferably, bebuffered to a pH of about 6.4 to 6.9 during formulation, and willmaintain the isolated populations of polynucleotides in a similar pHrange when the sample is contacted with the storage/collectionformulations described herein. Buffering capacity of the buffer and/orthe composition is preferably maximized by matching the buffer's pKavalue with the pH of the composition. Variations between pKa and pH arepreferably equal to or less than ±1.0, ±0.75, ±0.5 or ±0.25. Preferablythe buffering capacity variation between pKa and pH is +1.0, +0.75, +0.5or +0.25, or −1.0, −0.75, −0.5 or −0.25, which may relate to theparticular buffer used and the initial pH of the composition beforebuffer is added as determined by one skilled in the art.

The compositions of the present invention will typically at leastsubstantially inactivate, and preferably entirely inactivate, anyendogenous or exogenous RNAses, DNAses or proteases present in thesample, such that the nucleic acids of the sample are substantially freeof any degradation, and preferably do not degrade, or lose integrity,during the collection, lyses, concentration, storage, and transport ofthe sample for subsequent in vitro analyses.

Exemplary formulations of the storage/transport/collection compositionsof the invention are described in the examples herein, and include,without limitation, a composition that includes about 4 M of a chaotrope(such as guanidine thiocyanate, guanidine hydrochloride, guanidineisocyanate, or any combination thereof), about 10 mM to 30 mM of achelator (such as EGTA, HEDTA, DTPA, NTA, EDTA, citrate anhydrous,sodium citrate, calcium citrate, ammonium citrate, ammonium bicitrate,citric acid, diammonium citrate, ferric ammonium citrate, lithiumcitrate, or any combination thereof), about 0.25% of a detergent (suchas SDS, LDS, NaTDC, NaTC, NaGC, NaDC, sodium cholate, NaABS, NLS, or anysalt or combination thereof), about 0.1 M of a reducing agent (such asβ-ME, DTT, DMSO, formamide, TCEP, or any combination thereof), about0.1% of a surfactant/defoaming agent (such as a silicone polymer [e.g.,Antifoam A®] or a polysorbate [e.g., Tween®], or any combinationthereof), and about 1.0 μg/100 μl of magnetic affinity beads.

Additional exemplary formulations of the specimen collectioncompositions of the invention include, without limitation, a compositionthat includes about 3 M of a chaotrope (such as guanidine thiocyanate,guanidine hydrochloride, guanidine isocyanate, or any combinationthereof), about 1 mM of 0.5 M reducing agent (such as, e.g., β-ME, TCEP,formamide, DTT, DMSO, or any combination thereof), about 1 to about 10mM of a chelator (such as, e.g., EGTA, HEDTA, DTPA, NTA, EDTA, citrateanhydrous, sodium citrate, calcium citrate, ammonium citrate, ammoniumbicitrate, citric acid, diammonium citrate, ferric ammonium citrate,lithium citrate, or any combination thereof), about 0.25% of a detergent(such as SDS, LDS, NaTDC, NaTC, NaGC, NaDC, sodium cholate, NaABS, NLS,or any salt or combination thereof), and optionally but preferably about0.0002% of a defoaming agent (also referred to as an antifoaming agent)(such as a silicone polymer or a polysorbate, or any combinationthereof), about 100 mM of a buffer (such as Tris, MES, BES, Bis-Tris,HEPES, MOPS, bicarbonate, citrate, phosphate, or any combinationthereof), and about 1.0 μg/100 μl of magnetic affinity beads.

Another exemplary formulation of the disclosed polynucleotide isolationand stabilization compositions include, without limitation, acomposition that includes about 1 to about 4 M of a chaotropic agentsuch as guanidine thiocyanate, guanidine hydrochloride, or guanidineisocyanate; about 0.5 to 100 mM of a chelating agent such as EDTA, orsodium citrate, or both; about 0.1 to about 1% of an anionic detergentsuch as SDS or N-lauroyl sarcosine, sodium salt; about 0.001% to about0.0001% of a surfactant or wetting agent such as the silicone polymer,Antifoam A®, e); about 10 to about 500 mM of a buffering agent such asTris-HCl; about 10% to about 25% of a short-chain alkanol such asethanol, and about 1.0 μg/100 μl of magnetic affinity beads.

In particular embodiments, the invention provides a composition thatincludes about 2.5 M guanidine thiocyanate; about 0.5 mM TCEP; about 10mM sodium citrate; about 0.4% N-lauroyl sarcosine, sodium salt; about0.0002% Antifoam A, about 100 mM Tris-HCl, about 0.1 mM EDTA; about 23%ethanol, and about 1.0 μg/100 μl of magnetic affinity beads.

The invention also provides a method for obtaining a population ofnucleic acids from a sample. The method generally involves associatingthe sample with an amount of one of the compositions of the inventionunder conditions effective to obtain a population of nucleic acids fromthe sample. The invention optionally includes a facilitated release ofthe DNA/RNA from cells or cell structures of the biological sample andan affinity concentration of the desired population of nucleic acids forlater nucleic acid and/or sequence analysis.

The invention also provides a method of preparing a one-step aqueousformulation of the collection/lysis/transport/storage compositionsdescribed herein for the collection of nucleic acids such as RNA and/orDNA. In an overall sense, the method generally involves combining one ormore chaotropes and nuclease-free water at a temperature of about 20° C.to 90° C. in a reaction zone; then combining the dissolved one or morechaotropes with one or more reducing agents, one or more chelators, andone or more detergents in the reaction zone to form an intermediatecomposition; optionally combining a silicone polymer with theintermediate composition in an amount sufficient to minimize foamingduring further preparation of the one-step aqueous formulation;combining a sufficient amount of buffer to the intermediate compositionto maintain a pH of about 6 to 7.0; optionally combining a secondchelating agent to the reaction zone; then increasing the temperature ofthe second intermediate composition to about 60° C. to 95° C. for about1 to 30 minutes and lowering the temperature to ambient conditions;optionally then combining a C₁₋₆ alcohol with the contents of thereaction zone; and optionally adjusting the pH to be about 6.4 to 6.9and adding the nucleic acid capture material.

In additional embodiments, the invention provides a method for preparingone-step aqueous formulations adapted to obtain a population of nucleicacids from a biological sample or specimen. This method generallyinvolves at least the steps of: a) contacting the sample with an amountof the one-step aqueous formulation effective to: i) at leastsubstantially kill or inactivate potentially-infectious pathogens in thesample; ii) at least chemically or physically lyse a portion of cells torelease the desired nucleic acids from the sample; and iii) at leastsubstantially inhibit or prevent the released nucleic acids in thesample from further hydrolysis or enzymatic degradation, modification,or inactivation, so as to obtain the population of the desired nucleicacids from the sample.

Preferably, the methods of the invention will include at leastcontacting the sample with an amount of one or more of the disclosedcompositions at a temperature of from 0° C. to about 40° C. (morepreferably at a temperature of 4° C. to about 35° C., and still morepreferably at a temperature of 10° C. to about 30° C. or ambienttemperatures) for a period of time of at least 15 minutes, morepreferably at least 30 minutes, and more preferably at least 8 to 24hours. During contact with the composition and for all times thereafter,the desired nucleic acids remain substantially intact so as to bedetectable without incurring substantial deterioration, degradation,enzymatic cleavage, and/or digestion, modification, or other processing.

Preferably, the integrity of a population of nucleic acids released fromthe sample into the composition are substantially maintained, even whenthe composition comprising the sample is stored at ambient temperatures,and even for prolonged periods of time, including, without limitation,storage for greater than about 2 days, greater than about 5 days,greater than about 10 days, greater than about 20 days, or even greaterthan about 30 days or more. Likewise, it is desirable that the integrityof a population of nucleic acids released from the sample into thecomposition will be substantially maintained, even when the compositioncomprising the sample is stored at subtropical and tropicaltemperatures—even for prolonged periods of time, including, withoutlimitation, storage for greater than or equal to about 5 days, greaterthan or equal to about 10 days, greater than or equal to about 15 days,or even greater than or equal to about 20, about 25, about 30, about 35,about 40, about 60, or about 90 days or even greater.

In the practice of the present methods, it is preferable that at leastone or more biological cells contained within the sample aresubstantially lysed to release at least a first population or firstplurality nucleic acids contained within such cells into thecomposition. Preferably, the components of the disclosed composition aresufficient to release and thereafter isolate through affinity binding toa matrix material such a population from all or substantially all of theunwanted cellular/tissue and/or sample debris (including, withoutlimitation, lipids, phospholipids, peptides, proteins, polysaccharides,lipopolysaccharides, polyols, cellular organelles, membrane components,and such like).

It is also desirable in the practice of the present methods that whenone or more microbes, viruses, fungi, and/or other pathogens ororganisms of interest are present in, on, or about the sample whencollected, such microbes, viruses, fungi, and/or other pathogens ororganisms of interest will be lysed, sufficiently inactivated, orsubstantially killed upon contact with the composition, whichfacilitates safe handling of the sample by the practitioner. Preferably,one or more components of the disclosed composition are effective torender a pathogenic sample substantially or preferably entirely,non-pathogenic without the need for adding additional components to thecomposition. However, in certain applications, it may also be desirableto include one or more additional anti-microbial, anti-viral, oranti-fungal agents to the compositions to render them substantiallynon-pathogenic, and thus, safe for handling by the practitioner.

Preferably, the composition containing the sample is at leastsufficiently stable to permit storage of the sample in the compositionat ambient, near-ambient, or even colder or warmer conditions at leastsubstantially (or entirely) from the time of specimen or samplecollection substantially until the time of analyzing or characterizingat least a first population of nucleic acids from within the sample. Asused herein, “ambient temperature” can refer to temperatures of about18° C. to 25° C., or in some embodiments, more preferably from about 20°C. to about 22° C.

Preferably, composition containing the sample suspected of containingdesired nucleic acids stabilize and isolate the nucleic acids to theextent that they either remain at least substantially non-degraded(i.e., at least substantially stable) even upon prolonged storage of thecomposition at ambient, refrigerator, or sub-zero temperatures. It isdesirable that this stability provides that at least about 70%, at leastabout 85%, more preferably at least about 90%, more preferably at leastabout 95%, or even more preferably, at least about 98% of the nucleicacids contained within the stored sample will not be degraded uponprolonged storage of the sample. In certain embodiments, substantiallyall of the desired nucleic acids contained within the sample will bestabilized such that their original integrity is preserved during thecollection, lysis, storage, and transport of the processed sample.

Another embodiment of the invention comprises the surprising synergy ofmagnetic beads with MTM (e.g. PrimeStore™) that is achieved in methodsfor the extraction of total nucleic acid or targeted sequences. It wassurprisingly discovered that nucleic acids can be screened and isolatedfrom biological samples quickly, with sensitivity and with superioryields as compared to conventional procedures when using a methodologythat combines MTM such as PrimeStore™ with magnetic capture using SiO₂beads combined with carboxy magnetic beads (e.g., within a generatedmagnetic or electromagnetic field or with a magnet placed insufficiently close proximity). In this embodiment, sample is collectedin an MTM medium such as preferably PrimeStore™ to which is addedmagnetic capture material such as magnetic beads of, preferably, silicadioxide. Other types of beads are equally useful including glass beadsand also magnetic materials that are not beads such as, for example,other magnetic matrix materials, resins and polymers. Total nucleic acidis captured by the magnetic materials and easily and quicklyconcentrated with a magnet, electro-magnetic field or other electricalfield. Liquid may be removed and a second transition or intermediatebuffer added designed to change pH in anticipation of a third buffer.This second buffer prevents clumping of cellular debris to the silicabeads and releases the nucleic acids from the silica beads. Preferablythe second or intermediate buffer has a pH of 7 or higher, of 8 orhigher, or of 9 or higher and assist in the release of nucleic acidsfrom the first matrix material. Preferably, the intermediate bufferfunctions synergistically with the third or binding buffer. The thirdbuffer comprising preferably carboxy-modified magnetic matrix materialand PEG/salt allow or encourage the binding of the released nucleicacids to the carboxy-modified matrix. The binding buffer plus thecarboxy-modified matrix that are suspended serve a number of roles. Ahigh salt component and presence of PEG reduce dieletric constant andenhance charge shield, respectively, which enable the negative phosphatebackbone of RNA and DNA to bind to the net negative charge on thecarboxyl terminus of the matrix material. This enhances efficientbinding of minute concentrations of nucleic acids. Preferably thebinding buffer includes a detergent (e.g., Tween-20, Triton-X), and NLSwhich promote further lysis and degradation of lipid bilayers. Alsopreferably the binding buffer contains ethanol which improves bufferingviscosity and nucleic acid precipitation to the suspended matrix.Preferably, the binding buffer contain PEG (e.g., PEG-8000 at 15-20%),salt (e.g., NaCl at 1-2M), a buffering agent (e.g., Tris-HCl at 5-50mM), detergent (e.g., Tween-20 at 0.01-0.1% and/or Triton-X at0.01-0.10%), NLS (e.g., at 0.1-1.0%), an alcohol (e.g., ethanol at15-30%), and matrix material (e.g., carboxy beads at 0.1 to 10.0 mg/ml).

In this embodiment, the nucleic acids are concentrated at two-fold orgreater concentrations than when using traditional chromatographytechniques, preferably five-fold or greater concentrations, morepreferably ten-fold or greater concentrations, and more preferablytwenty-fold or greater concentrations. Preferable the beads are coupledwith an agent such as, for example, a carboxy group that specificallybinds to a target nucleic acid sequence of interest.

Alternative, beads may contain modifications that bind to specificsequences. Such modifications may be chemical that promote bindingbetween the bead and a certain chemical (e.g., A, G, C, T, U) orstructural (e.g., lock and key binding). Modifications may compriseaptamers and/or specific sequences. Once bound, the beads, which arepreferably magnetic, once again can be easily and quickly isolated andthe target sequence eluted, which can be directly eluted into a nucleicacid detection assay such as, preferably, PCR, gene or whole genomesequencing, Ion Torrent Sequencing, Next Generation Sequencing and thelike. As carboxy groups and most other chemical modifications of beads(e.g. modifications that create pendant groups) would be destroyed inPrimeStore™, the same beads can be used throughout the process—first toisolate all nucleic acids from the sample, wherein the carboxyfunctionality is not utilized, then to isolate specific nucleic acidsequences, wherein the carboxy functionality is utilized. Silica beadsare also preferred for extraction step from PS and carboxy beads for theisolation of the target sequences. This process provides the additionaladvantage that the liquid from which the target nucleic acid was elutedremain intact and otherwise unaffected by any harsh or deleteriouschemicals. Thus, the nucleic acids depleted of one target sequence canbe re-analyzed for another, different target sequence. As the nucleicacids of the biological sample are returned to a stable condition withan MTM such as PrimeStore™, they can be re-used and re-tested repeatedlyfor the identification and isolation of many different target sequencesof interest. A preferred method therefore involves placing thebiological sample in PrimeStore, adding magnetic beads to couple withnucleic acids of the sample, isolating the beads and eluting the nucleicacid, adding additional magnetic beads but coupled with a carboxy groupthat specifically targets a nucleic sequence of interest, isolatingthose beads and eluting the target nucleic acid for subsequent DNAanalysis such as PCR. The nucleic acid recover at each step is superiorto conventional procedure and minimizes any need for a differentsolution or for different equipment at each step. Determining the amountor quantity of beads needed for each step can be determined fromempirical information of determined experimentally.

Another embodiment of the invention is directed to systems whereby oneor more biological samples are maintained in a MTM such as PrimeStore™and subjected to an automated process that involves one or more cyclesof isolation of targeted nucleic acid sequences. Optionally the verysame MTM can be used throughout the process as can the very same beads,but for the beads used for targeting of specific nucleic acid sequences.High through-put devices can process many samples and detectionssimultaneously and with consistency, and without the inconsistenciesthat can be attributed to human error. This targeted process enrichesthe nucleic acids of the biological sample by removing a non-targetsequence at each step. In other words, it becomes easier to identifyand/or isolate each rare red marble from a background of many bluemarbles by gradual elimination of the blue marbles.

Advantages of the preferred process of the invention utilizingPrimeStore™ and magnetic beads includes, but is not limited to fasterprocessing and achievement of results, minimizing the number andcomplexity of steps and therefor associated costs. In addition, asPrimeStore™ can be utilized at ambient temperatures and contains noingredients that would interfere with DNA testing, the entire process ofidentifying nucleic acid targets is simplified and streamlined.

The present invention also provides kits and sample collection systemsutilizing the disclosed compositions andcollection/storage/transport/isolation solutions described herein. Inparticular embodiments, such sample collection systems may include acollection device, such as a swab, curette, or culture loop; and acollection vessel, such as a vial test tube, or specimen cup, thatcontains one or more of the compositions disclosed herein. Thecollection vessel is preferably releasably openable, such that it can beopened to insert the one-step compositions and closed and packaged,opened to insert the sample and optionally a portion of the collectiondevice and closed for storage and transport, or both. The collectionvessel may use any suitable releasable or openable mechanism, includingwithout limitation a screw cap, snap top, press-and-turn top, or thelike. Such systems may also further optionally include one or moreadditional reagents, storage devices, transport devices, and/orinstructions for obtaining, collecting, lysing, storing, or transportingsamples in such systems. In a preferred embodiment, the one-stepcompositions of the invention may already be disposed in the reactionzone into which the sample may be associated. In such embodiments, theinvention requires only a collection device and the collection vessel.The kit preferably includes one or more isolation or extraction elementsto help liberate and/or separate one or more populations of nucleicacids contained within the sample from one or more other biomolecules orsample components to obtain at least partially, or substantiallypurified nucleic acids suitable for identification, detection, orfurther molecular analysis.

A preferred embodiment of the invention comprises compositions andmethods comprising magnetic beads coated with a material that binds toRNA and/or DNA. These beads preferentially bind, for example, to MTBmessenger RNA and/or DNA. Optionally, aliquots of the specimen inPrimeStore may be transferred to magnetic beads or filters to separateDNA from RNA. In one approach, mRNA or siRNA is filtered using sizerestricted filters. The DNA and/or RNA purified from PrimeStore is thendetected with standard real-time PCR to MTB specific targets. A ratio ofMTB RNA to DNA is analyzed to determine the change in viable MTB aftertherapy. Magnetic beads that bind RNA or DNA can be substituted forsilica coated magnetic beads depending on the chemical composition ofthe binding solution. After the RNA or DNA are bound, they are elutedusing an eluding solution and quantitated using real-time MTB specificPCR. One advantage of this approach is that the MTB are already lysed inthe PrimeStore collection solution and specimen aliquots can go directlyto filters or magnetic beads for either RNA or DNA isolation. Thisspeeds the lab workflow for rapid MTB PCR RNA/DNA detection.

A preferred kit comprises beads suspended in a buffer foradherence/binding of RNA and/or DNA to bead surfaces for extraction ofnucleic acids from biological samples. Preferably the buffer comprisescomponents that do not alter the functionality of the beads, such as thefunctionality of carboxy beads. Preferably, components for a buffer donot include chaotropic agents, but includes agents to effectively bindnucleic acids (e.g., polyethylene glycol and NaCl) plus additionalreagents and/or agents hat are surfactants (e.g., Tween-20, Triton-X andethanol and/or agents that promote further processing of cells andcellular debris (e.g., lysing, degradation of non-nucleic acidpolymers).

Also, kits may be packaged for commercial distribution, and may furtheroptionally include one or more collection, delivery, transportation,storage and/or isolation devices for sample or specimen collection,handling, or processing. The container(s) for such kits may typicallyinclude at least one vial, test tube, flask, bottle, cup, or othersuitable container or collection device, into which the composition(s)may be placed, and, preferably, suitably aliquotted for individualspecimen collection, transport, and/or storage. The kit may also includea larger container, such as a case, that includes the smaller,individual containers noted above, along with other collection devices,equipment, reagents, instructions, and/or the like. The kit may alsooptionally include one or more additional buffers, compounds, orcompositions, and may also further optionally include one or moreinstructions detailing use(s) of the kit in either the collection orstorage of one or more biological, clinical, diagnostic, environmental,or forensic sample. Optionally, the kit may also further provideinstructions for the transport of the sample once placed in one or moreof the disclosed compositions, and may even include instructions oradditional reagents detailing one or more subsequent analytical methodsor assays employing the nucleic acids isolated from the sample orspecimen. Such kits may also include multiples of the various collectiondevices and collection vessels and any other components to be included,so that the kits can be used to collect multiple samples from the samesource or different sources. In one commercial application, the kits arepackaged in sets of five or more for convenient sale and use.

Optionally, compositions of the invention may include an appropriatedetectable marker (i.e., a “label”) for determining the presence of thenucleic acid of interest. A wide variety of appropriate indicatorcompounds and compositions are known in the art, including, withoutlimitation, fluorescent, radioactive, enzymatic or other ligands, suchas avidin/biotin, etc., which are capable of being detected. It may bedesirable to employ a fluorescent label or an enzyme tag such as urease,alkaline phosphatase or peroxidase, instead of radioactive or otherenvironmentally less-desirable reagents. In the case of enzyme tags,colorimetric, chromogenic, or fluorigenic indicator substrates are knownthat can be employed to provide a method for detecting the sample thatis visible to the human eye, or by analytical methods such asscintigraphy, fluorimetry, spectrophotometry, and the like, to identifyspecific nucleic acids.

In general, probes described will be useful both as reagents in solutionhybridization, as in PCR, for detection of particular nucleic acidsequences, as well as in embodiments employing a solid phase. Onewell-known amplification method is the polymerase chain reaction(referred to as PCR) which is described in detail in U.S. Pat. Nos.4,683,195, 4,683,202 and 4,800,159, and each incorporated herein byreference in entirety. Another method for amplification is the ligasechain reaction (“LCR”), disclosed, e.g., in EPA No. 320 308, and U.S.Pat. No. 4,883,750, each of which is incorporated herein in its entiretyby express reference thereto. Strand Displacement Amplification (SDA) isanother method of carrying out isothermal amplification of nucleic acidsthat involves multiple rounds of strand displacement and synthesis,i.e., nick translation. A similar method, called Repair Chain Reaction(RCR), involves annealing several probes throughout a region targetedfor amplification, followed by a repair reaction in which only two ofthe four bases are present. The other two bases can be added asbiotinylated derivatives for easy detection. A similar approach is usedin SDA. Target specific sequences can also be detected using a cyclicprobe reaction (CPR). In CPR, a probe having 3′ and 5′ sequences ofnon-specific DNA and a middle sequence of specific RNA is hybridized toDNA that is present in a sample. Upon hybridization, the reaction istreated with RNase H, and the products of the probe identified asdistinctive products that are released after digestion. The originaltemplate is annealed to another cycling probe and the reaction isrepeated.

The following examples illustrate embodiments of the invention, butshould not be viewed as limiting the scope of the invention.

EXAMPLES

Once formulated, the stock solutions of PrimeStore™ are stable at 4° C.or below for periods of at least one year or more. FormulatedPrimeStore™ solutions (PSSs) are stable at ambient temperature (e.g.,about 20-30° C.) for periods of many months. Once a sample is contactedwith a PrimeStore™ formulation, the mixture can be stored indefinitelyat temperatures of 0° C. or below, at least one year or more underrefrigeration (e.g., ≈4° C. and at least 30 days or more at ambienttemperature (e.g., about 20-30° C.), without significant loss of nucleicacid composition, fidelity or integrity of the sample. For example,without limitation, the integrity of a population of polynucleotidesobtained from the sample is at least substantially maintained, andpreferably entirely maintained without detectable degradation, when thecomposition comprising the sample is stored at a temperature of fromabout minus 20° C. to about plus 40° C., for a period of from about 0days to about 60 days or more.

Example 1—Formulation of Exemplary Storage Solutions

The present example provides a general formulation of the PSScompositions of the present invention. Additional formulations of thePSS compositions are exemplified in Examples 2 through 5.

Formulation Ranges of Exemplary Components for the Preparation ofPrimeStore™ Compositions

Compound Final Concentration Range (examples) A chaotrope, e.g.:Guanidine thiocyanate about 0.5M to about 6M and/or Guanidinehydrochloride about 0.5M to about 6M and/or Guanidine isocyanate about0.5M to about 6M An anionic detergent, e.g.: N-lauroyl sarcosine (interalia Na salt) about 0.15% to about 1% (wt./vol.) and/or Sodium dodecylsulfate, about 0.15% to about 1% (wt./vol.) Lithium dodecyl sulfate,about 0.15% to about 1% (wt./vol.) Sodium glycocholate, about 0.15% toabout 1% (wt./vol.) Sodium deoxycholate, about 0.15% to about 1%(wt./vol.) Sodium taurodeoxycholate, and/or about 0.15% to about 1%(wt./vol.) Sodium cholate about 0.10% to about 1% (wt./vol.) A reducingagent, e.g.: TCEP about 0.05 mM to about 30 mM and/or β-ME, DTT,formamide, or DMSO about 0.05M to about 0.3M 4. A chelator, e.g.: Sodiumcitrate about 0.5 mM to about 50 mM and/or EGTA, HEDTA, DTPA, NTA, APCA,etc. about 0.01 mM to about 1 mM A buffer (e.g., TRIS, HEPES, Bis-Tris,etc.) about 1 mM to about 1M An acid (e.g., HCl or citric acid) q.s. toadjust to a pH of about 6 to 7, preferably about 6.8 to 7.0Nuclease-free water q.s. to desired final volume Optionally one or moreof: A surfactant/defoaming agent, e.g.: Antifoam A ® or Tween ® about0.0001% to about 0.3% (wt./vol.) An alkanol (e.g., methanol, ethanol,propanol, etc.) about 1% to about 25% (vol./vol.) A carrier/IPC RNAand/or DNA about 1 pg to about 1 μg/μL Magnetic NACM about 1 ng to 10 mgper 1 mLGuanidine thiocyanate, sodium citrate, Antifoam A® Concentrate, andN-lauroylsarcosine, sodium salt, were all purchased from Sigma ChemicalCo. (St. Louis, Mo., USA). Tris(2-carboxyethyl)phosphine hydrochloride(TCEP) was obtained from Soltec Ventures Inc. (Beverly, Mass., USA).2-amino-2-hydroxymethyl-propane-1,3-diol (TRIS) was obtained fromApplied Biosystems/Ambion (Austin, Tex., USA).2-[2-(Bis(carboxymethyl)amino)ethyl-(carboxymethyl)amino]acetic acid(EDTA) GIBCO® Ultra Pure was obtained from Invitrogen Corp. (Carlsbad,Calif., USA). All other reagents are available commercially fromSigma-Aldrich or USB Corporation.

Example 2—Formulation of an Exemplary Storage Solution

The present example describes a first exemplary formulation of thecompositions of the invention. This formulation is alternativelyreferred to as “PrimeStore™ Solution” or “PSS” version 1.

Preparation of PrimeStore™ Composition (Version 1)

Compound Final Conc. Guanidine thiocyanate 4M Sodium citrate 30 mMSodium dodecyl sulfate 0.25% (wt./vol.) N-lauroyl sarcosine, sodium salt0.25% (wt./vol.) 2-mercaptoethanol (β-ME) 0.1M Antifoam A 0.1%(wt./vol.) Citric acid q.s. to adjust pH to 6.5 Nuclease-free water11.82 mL Magnetic NACM beads 80 mg

Example 3—Preparation of a Second Exemplary Storage Solution

The present example describes the preparation of another exemplarystorage solution according to the present invention. This formulationmay be referred to as PSS, which is PrimeStore™ version 2.

Preparation of PrimeStore™ Composition (Version2)

Compound Quantity Final Conc. Guanidine thiocyanate 35.488 gm 3M TCEP0.02867 gm 1 mM Sodium citrate 0.2931 gm 10 mM N-lauroyl sarcosine,sodium 0.5 gm 0.5% salt (NLS) Antifoam A (10% solution) 200 μL 0.002%TRIS (1M) 10 mL 100 mM EDTA (0.5M) 20 μL 0.1 mM Hydrochloric acid (HCl)q.s. to adjust pH to 6.9 — Nuclease-free water q.s. to 100 mL — MagneticNACM beads 80 mg 0.8 mg/mL —

Example 4—Preparation of a Third Exemplary Storage Solution

The present example describes the preparation of another exemplarystorage solution according to the present invention. This formulation isalso referred to as PSS or PrimeStore version 2.2.

Preparation of PrimeStore™ Composition (Version 2.2)

Compound Quantity Final Conc. Guanidine thiocyanate 29.574 gm 2.5M TCEP0.01434 gm 0.5 mM Sodium citrate 0.2931 gm 10 mM N-lauryl sarcosine,sodium salt (NLS) 0.4 gm 0.4% Antifoam A (10% solution) 200 μL 0.002%TRIS (1M) 10 mL 100 mM EDTA (0.5M) 20 μL 0.1 mM Ethanol, molecular grade(96-100%) 23 mL 23% (vol./vol.) Hydrochloric acid (HCl) q.s. to adjustpH — to 6.9 Nuclease-free water q.s. to 100 mL — Magnetic NACM beads 80mg 0.8 mg/mL

Example 5

The inactivation of gram-positive mycobacteria (e.g., inactivation ofnucleases, sterilization of microorganisms) from sputum or othermucous-containing specimens that are contaminated with other organismsis difficult since mycobacteria are often shielded by the highly viscoussputum mucous content within the sample. The components present in PSSsafely inactivate 10⁸ concentrations of mycobacterium through chemicalinactivation/killing by phospholipid membrane shearing, proteindenaturation, chelation and buffering effect. However, mycobacteriapresent in collected primary sputum samples that contain human serumalbumin, mucopolysaccharide and mucoprotein fractions may shield andprotect the organism from direct inactivation by chemical inactivationmechanisms in PSS. Additional strategies to enhance mycobacteriainactivation from primary sputum samples collected in PSS includephysical agitation using various sized porcelain, ceramic, plastic orglass beads. When combined with vortexing, the physical disruption ofsputum matrix exposes the organism to PSS and facilitate greaterinactivation. Furthermore, the same or different beads that are coatedwith silica dioxide and magnetized are used to bind and concentratereleased DNA and RNA from inactivated cells and microbes though thechemical processes of PSS. The prerequisites for high affinityattachment of nucleic acid (DNA/RNA) to silica are: 1) a preferred pH of6.8-7.0, and 2) a preferred presence of a chaotrophic agent. Both ofthese preferences are existing features of PSS formulation. PSScontaining beads facilitates killing of mycobacteria in primary sputumsamples. The further addition of magnetized, silica coated beads used incollection tubes and in combination with a magnetic stand concentratesnucleic acids from primary samples as well. In addition to physicalagitation through bead-based vortex, the addition of heating (within atemperature range of 50−90° C.) and or sonication enhances inactivationand killing of mycobacteria in primary sputum samples.

Example 6 Exemplary Protocol for the Preparation of PSS

40 mL of nuclease-free water is first added to a clean beaker with astir bar. The beaker is placed on a hot plate/stirrer and adjustedtemperature to 60° C.-65° C. Stirring speed is set to medium and 29.574gm of guanidine thiocyanate is added slowly to the water allowing it todissolve as added. Next, 0.01434 gm of TCEP is added to beaker andstirrer speed increased to help dissolve crystals. 0.2931 gm of sodiumcitrate is added to the beaker followed by 0.4 gm of NLS to thesolution. Stirrer speed is then increased again to create a vortex inthe beaker. This vortex pulls the NLS into the solution and helps todissolve reagent. A prepared 10% Antifoam A solution (1 mL Antifoam AConcentrate +9 mL nuclease-free water) is vortexed and 200 μL of the 10%Antifoam A is pipette into the solution. Next, 10 mL of 1 M TRIS isadded into the solution and 20 μL of 0.5 M EDTA. Temperature isincreased to bring the solution to 75-80° C. with stirring for 3-5minutes. The beaker is removed from heat and the solution allowed tocool to room temperature (≈22-25° C.). 23 mL of ethanol is added to thesolution and mixed thoroughly, and the pH is adjusted to 6.9+/−0.1 withHCl. Solution is poured into a clean 200 mL graduated cylinder. 80 mgmagnetic affinity matrix beads are added along with nuclease-free waterto bring total volume to 100 mL. The solution is transferred to alabeled sterile container and stored at room temperature (≈22° C.−25°C.). Preferably each reagent is completely dissolved before adding thenext.

Example 7 Protocol for the Preparation of PrimeStore™ with MagneticBeads Extraction

PrimeStore MTM™ was prepared as a 1.5 mL solution in 3 mL cryovialtubes. Two types of commercially available silica coated, magnetizedbeads (MagAttract Material No. 1031699, Qiagen, and Agencourt, BeckmanCoulter, Inc) were used for this example. A total of 100 μL of beads wasadded to PrimeStore MTM™ tubes. A purified strain of Mycobacteriumtuberculosis (H37Rv) that was inactivated by gluteraldehyde andsonication was used at a concentration of 10³ CFU/mL. Mycobacteriumtuberculosis (MTB) was added to PrimeStore™ tubes containing magneticbeads and PrimeStore™ Tubes without magnetic beads (control).PrimeStore™ tubes were vortexed 5-10 seconds and tubes with beads weresubsequently attached on top of a magnet for 2 minutes to attract tubeswith beads to the bottom. While on the magnet, the PrimeStore™ tubeswere uncapped and the solution was removed. Tubes were removed from themagnet and 200 μL of nuclease free water was added to the beads. Eachtube was vortexed to elute nucleic acids from the beads. The PrimeStore™tube was placed back on the magnet for 2 minutes to draw beads to thebottom. The eluate was transferred into a microcentrifuge tube. 200 μLof PrimeStore™ (without magnetic beads) containing MTB was removed andplaced into a microcentrifuge tube to serve as an unconcentratedcontrol. The 200 ul aliquots from bead-concentrated and control tubeswere subjected to nucleic acid extraction using the Qiagen DNA Mini Kit(Qiagen Inc., Valencia, Calif.). Purified nucleic acids from bothextraction procedures were amplified in replicate fashion using areal-time PCR assay on the ABI 7500 Real Time PCR System. Detection fromPrimeStore MTM™ with magnetic beads had replicate C_(T) values 28.50,whereas detection from PrimeStore MTM™ without magnetic beads hadreplicate C_(T) values of 29.78. The decrease in C_(T) values fromsamples that were concentrated using glass beads indicates a higherinitial template starting concentration. These results demonstrate thatsilica coated beads and likely other affinity matrix materials as anexample for any silica-coated matrix are compatible with PrimeStore MTM™solution. Also, capture with magnetic beads allows an increase inconcentration of nucleic acids from the sample prior to extraction, andenhances detection sensitivity. This allows for the concentration ofnucleic acids from low-level samples for the potential detection of thepresence or absence of pathogens in biological samples. Thus, themethodology is a simplified and efficient approach for concentratingminute quantities of nucleic acids (RNA and DNA) from collectedspecimens prior to extraction.

Example 8 Magnetized Beads with PrimeStore™ Molecular Transport Medium(MTM)

Magnetized bead types containing various surface coatings that includesilica dioxide, heterogeneous silica derived molecules, glass fibers,polystyrene, and carboxyl-coated beads were evaluated with commerciallyavailable molecular transport medium for sensitivity in the capture oftarget DNA and/or RNA sequences. Commercially available magnetized beadsare typically in the range of 0.5 to 10 micrometers (μM) in diameter.Additional sizes below and above this range are also commerciallyavailable and could be utilized. In addition to magnetized beads, othermagnetized materials may be used. PrimeStore™ Molecular Transport Medium(MTM) (commercially available from Longhorn Vaccines and Diagnostics,LLC, Bethesda, Md.) promoted high affinity and reversible binding of thenegatively charged phosphate backbone of RNA and/or DNA to silica-basedsurfaces. Reagents present in PrimeStore MTM™ (e.g., salts andguanidine-based compounds) coupled with a slightly acidic to neutral pH(i.e., pH 6.9) create the chemical environment needed for nucleic acidbinding to silica-derived compounds. When silica is coated on thesurface of magnetized beads and subsequently added at the properconcentration to tubes of PrimeStore MTM™, nucleic acids (RNA/DNA) ofvarious sizes from collected samples are bound with high affinity.

Silica beads can be used synergistically with PrimeStore MTM™ forcollection, transport, and processing of clinical, environmental, orlaboratory strains for microbes including bacteria, eukaryotic, or viralcells and pathogens. Magnetized silica beads present in PrimeStore™ bindnucleic acids, and using simple magnetism or electromagnetism, theDNA/RNA bound to beads can be used to concentrate samples collected inPrimeStore MTM™ after decanting the liquid volume of PrimeStore™.Samples include the usual range of clinical, environmental, orlaboratory-based cultures containing microbes of interest that areroutinely collected in PrimeStore MTM™. Examples of clinical specimensinclude, but are not limited to, sputum, nasal washings, throat swabs,fecal material or urine, buccal, blood, serum, vaginal, or other bodilysecretion. By concentrating samples in PrimeStore MTM™ containingmagnetized, silica-coated beads prior to performing standard/routinenucleic acid extraction, a marked (10 to 100-fold) increase in the finalextraction yields was seen as measured using quantitative real-time PCR.

Concentration step: A specimen is collected in PrimeStore MTM™containing a concentration of silica-coated, magnetized beads. A magnetis applied to the base of the tube where beads containing all nucleicacids are bound. After a 1-2 minute magnet exposure, PrimeStore™ liquidis removed by decantation using a micropipette leaving 0.2 to 0.4 mL inthe base of the tube. The magnet is removed and the remaining, nowconcentrated mixture of beads plus nucleic acids is pipetted directly toa commercial spin column for nucleic acid extraction (see FIG. 1).

In one example, the extraction yield of total genomic DNA fromMycobacterium tuberculosis was approximately 10 fold better when thisconcentration step was used prior to genomic DNA extraction compared toan equivalent volume that was not concentrated. In contrast to beadscontaining a silica dioxide coated surface, some commercial beadscontain a core of polystyrene, one or more layers of magnetite, and asurface coating containing carboxylate (i.e., COOH). Carboxylate-coatedbeads are commercially available from several vendors including GeneralElectric (GE) Health Care's SpeedBead Magnetic Carboxylate ModifiedParticles, Azide 0.05% (Part #65152105050250). Carboxylate beads placeddirectly in PrimeStore MTM™ did not bind nucleic acids, but have otherutilities.

In one embodiment, a total nucleic acid carboxyl bead extraction kitincluding buffers optimized for binding, washing, and eluting can beutilized with specimens/samples that are routinely collected, shipped,and transported in PrimeStore MTM™. In this methodology, the developednucleic acid extraction kit containing carboxylate beads and optimizedbuffers are compatible with PrimeStore MTM™ chemistry and used aftersample collection. This is different from common extraction performedusing a chaotrophic guanidine solution with silica dioxide spin columns(e.g., PrimeXtract, Qiagen spin columns, etc.) or silica magnetizedbeads (i.e., automated Roche MagnaPure™). An aliquot of 0.1 to 0.5 mL ofsample/specimen collected in PrimeStore™ is added to an optimized buffercontaining but not limited to: polyethylene glycol (PEG), sodiumchloride or other salts or combinations of salts, Polysorbate 20 orother surfactants/detergents, TRIS or other buffering agents, EDTA orother preservatives, that are optimized at the proper molarconcentrations to synergistically work with PrimeStore™ MTM such thatthe ratio of added Primestore™ plus sample to carboxyl bead bufferpromotes nucleic acid binding to carboxyl beads.

In another embodiment, a target specific nucleic acid carboxyl beadextraction kit including buffers optimized for binding, washing, andeluting can be utilized with specimens/samples that are routinelycollected, shipped, and transported in PrimeStore MTM™. For example,chemically modified carboxy beads containing highly conserved influenzasequences are used to capture minute concentrations of influenza virusRNA from clinical nasal washings or throat swab specimens in PrimeStoreMTM™. While viral RNA levels are contingent on the quality of thecollected patient specimen, the extraction yields improved by a highlyspecific “target capture” methodology that binds the minute RNA ofchoice and removes all other nucleic acids from the final elution. Inother words, the ability to capture a specific sequence is improved byreducing the majority of non-specific sequences that are also present.

Another embodiment of the invention involves a combinational use of beadtypes that work synergistically to: (a) concentrate total nucleic acidsfrom a sample thus removing unwanted proteins, carbohydrates, lipids,and other inhibitory compounds/reagents, and then (b)targeting/capturing a specific nucleic acid sequence, or set ofsequences. In this approach, specimens are collected in PrimeStore MTM™by routine methodology. The sample is concentrated using silica beadspresent in PrimeStore™ by magnet capture and the remaining liquid volumediscarded. Beads with bound nucleic acids are washed and/or eluted usingan elution buffer. The elution containing total nucleic acids is addedto a buffered solution containing modified carboxylate beads containinghighly conserved, hybridization oligonucleotides for capture of specificgenomic DNA (gDNA), mRNAs, siRNA, viral RNAs (vRNA) or other nucleicacid targets. An experiment comparing the extraction from a silicacolumn to extraction with PrimeStore™ (PS) plus magnetic beads is shownin FIG. 2 and summarized below.

Low-Level Concentration with Beads in Primestore™

MTB Extraction Method MTB Target (Triplicate C_(T) avg.) Silica Column,100 μl 38.8 Concentrated in PS (50 μl Beads) 32.3 MTB 6110 Assay MTBExtraction Method C_(T) Values Avg. Std. Dev. Silica Column, 100 μl 40.036.5 40.0 38.8 2.02 Concentrated in PS 31.9 32.9 32.1 32.3 0.67 (50 μlBeads) 31.6 32.7 32.8

As depicted in FIG. 2, this methodology is highly advantageous forapplications that rely on highly purified target sequences derived fromlow-level clinical specimens. For example, whole genome sequencing (WGS)from microbes procured directly from clinical specimens, e.g.,Mycobacterium tuberculosis from sputum.

100 μL of 10-2 diluted Stock MTB (gluteraldehyde-fixed) from BattelleInc. was pipetted into PrimeStore™ (DNA) tubes containing 1.5 mL ofvolume. Shown in FIG. 3 are PrimeStore MTM™ tubes (containing a varyingbead concentrations) that were concentrated using a simple magnet priorto spin column extraction. Using a magnet approximately 1.1 mL ofPrimeStore MTM™ was removed with a remainder of −400 μL in the tube. Theconcentrated 400 μL volume containing beads with bound DNA/RNA wastransferred directly from PrimeStore™ tubes into a silica spin columnfor extraction. In all experiments 400 μL was extracted by silica spincolumns and eluted in 50 μL of nuclease-free water. Results depicted inFIG. 3 are summarized below.

Concentrating Sample Using Silica Beads in Primestore™ Prior toExtraction

MTB Extraction Method MTB Target (Duplicate C_(T) avg.) Silica Column,100 μl 28.6 150 μl Beads 24.4  50 μl Beads 24.5  25 μl Beads 25.1  10 μlBeads 25.4 Silica Column, 1.5 ml 24.5 MTB Assay MTB Extraction MethodC_(T) Values Avg. Std. Dev. Silica Column, 100 μl 28.3 28.8 28.6 0.33150 μl Beads 24.6 24.3 24.4 0.24  50 μl Beads 24.4 24.5 24.5 0.07  25 μlBeads 25.5 24.8 25.1 0.49  10 μl Beads 25.2 25.5 25.4 0.22 SilicaColumn, 1.5 ml 24.6 24.4 24.5 0.11

The gold standard comparator (indicated as “Silica Column, 1.5 ml”; FIG.3) is an extraction of the entire 1.5 mL of PrimeStore™ solutioncontaining MTB through the filter column by multiple passages. Indicatedas “Silica Column, 100 μl” (FIG. 3) is extraction from PrimeStore MTM™containing no beads. Thus, using multiple passages the maximum nucleicacid recovery according to qPCR cycle threshold (C_(T)) values is 24.5compared to 28.6 when only 100 μL is extracted. Magnetized silica coatedbeads effectively concentrated the recovery of nucleic acids asindicated by C_(T) values in real-time PCR (indicated as “150 μl Beads”;“50 μl Beads”; “25 μl Beads”; “10 μl Beads”; FIG. 3). The PrimeStoreMTM™ tube containing 50 μL of beads was optimal and showed a 24.5 C_(T)value indicating comparable recovery compared to control (indicated asSilica Column, 1.5 ml). Importantly, there is 4.1 C_(T) difference orgreater than 10-fold improvement when samples are concentrated prior toextraction (compare bar shown as “Silica Column, 100 μl” with bars shownas “150 μl Beads”; “50 μl Beads”; “25 μl Beads”; “10 μl Beads”; FIG. 3).

In a next experiment, a formulated carboxy-friendly buffer was comparedto the proprietary buffer that Agencourt uses in its AMPure beadsolution. To accomplish this, three formulations were designed at LH(designated as “Longhorn Buffers”). An equal amount of total genomic MTBDNA (10⁴ CFU/mL) was added (1:2 ratio of MTB:Beads) to the buffer/beadmixture, cleaned with 80% ethanol, and eluted in 50 μL of water. Apositive control MTB reaction (indicated as “Positive Control, MTB”;FIG. 4) containing the exact concentration of MTB was used as the “bestcase” control to compared to the test reactions. Results depicted inFIG. 4 are summarized below.

Comparison of Buffers/Beads

MTB Target MTB Extraction Method (Duplicate C_(T) avg.) Longhorn Buffer(PEG 8000, NaCl) 30.9 Longhorn Buffer (PEG 8000, NaCl, Tris, Tween) 29.1Longhorn Buffer (PEG 1000, NaCl, Tris, Tween) 36.5 Agencourt AMPureBeads 29.7 Positive Control MTB 29.8 MTB 6110 Assasy MTB ExtractionMethod C_(T) Values Avg. Std. Dev. Longhorn Buffer 31.2 30.5 30.9 0.49(PEG 8000, NaCl) Longhorn Buffer 29.1 29.0 29.1 0.07 (PEG 8000, NaCl,Tris, Tween) Longhorn Buffer 35.9 37.0 36.5 0.78 (PEG 1000, NaCl, Tris,Tween) Agencourt AMPure Beads 29.5 29.8 29.7 0.21 Positive Control MTB29.8 29.8The Longhorn Buffer containing 8000 PEG and other reagents wasequivalent to the Agencourt AMPure bead buffer mixture. The carboxybeads used were provided by GE Healthcare.

Example 9 Extraction with Carboxylated Magnetic Beads Vs. Silica SpinColumns

FIG. 5 shows two surprising findings. First, PrimeStore MTM wasdetermined to be compatible with carboxy beads/optimized buffer. Thepathogen used was Mycobacterium tuberculosis in clinical samples, whichwas placed in PrimeStore MTM and then extracted using a buffer withmagnetized, carboxy beads. In FIG. 5, the first bar of each MTBconcentration shows the cycle threshold (Ct) when using spin columns forextraction (BLUE diagonal stripes). The second bar depicts Ct forcarboxylated beads at a concentration with sample of 2:1 (RED, nostripes). The third bar depicts Ct for carboxylated beads at aconcentration with sample of 4:1 (GREEN horizontal stripes). The MTBconcentration used was stock, 10̂-1 dilution of stock, 10̂-2 dilution ofstock, 10̂-3 dilution of stock, 10̂-4 dilution of stock and 10̂-5 dilutionof stock. The lower Ct achieved with carboxylated beads in buffer ascompared with Ct values from spin columns demonstrate increaseddetection. The buffer comprised PEG-8000 at 15.68%, NaCl at 1.96M,Tris-HCl at 8 mM, EDTA at 0.8 mM, Tween-20 at 0.08%, Tritin-X at 0.08%,MLS at 0.32%, and ethanol at 20%, which when included, contained carboxybeads at 1 mg/ml.

Surprisingly, when compared with extraction of these same samples usingsilica spin columns, the overall extraction performance for carboxy-beadextraction was slightly better across a 6-log dynamic range of titeredpathogen compared to standard, widely used spin column purificationusing silica columns.

Example 10 Carboxy Bead Extraction

Buffer D was prepared in 100 mL conical tube with 49 mL PEG-8000/NaCl(2.5M NaCl and 20% PEG) (final conc. 15.68%), 0.5 mL 1 M Tris-HCL (finalconc. 1.96M), 0.1 mL EDTA (final conc. 8 mM), 50 μL of Tween-20 (finalconc. 0.08%), 50 μL of Triton-X (final conc. 0.08%), 0.2 grams NLS(final conc. 0.32%), 12.5 mL of 100% Ethanol (final conc. 20%), and 0.4mL of GE carboxy beads suspended in TE (10 mM Tris-HCl, 1 mM EDTA)prepared by cleaning 1 mL of fully mixed stock GE beads (50 mg/mL), andwashing 3× with magnet and TE buffer or purified water. Re-suspend the50 mg of Stock GE beads in 0.4 mL of TE buffer and add to preparedbuffer D. To make Adenovirus/PrimeStore dilutions (thereby simulatingnucleic acids of a biological sample but standardized for comparativepurposes), whole Adenovirus culture was diluted 1.0 mL into 9.0 mL ofPrimeStore and serially diluted from 10⁻¹-10⁻⁸ dilutions. StockAdenovirus was not used for these experiments. 200 uL of each Adenovirusdilution was placed in a series of 1.5 mL microcentrifuge tubes.Depending on the type of extraction method, 200 uL spin column, 300 uLSaline-Life Tech 600 uL GE or ReSyn carboxybeads were used in singletsto test for extraction efficiency. With the spin column methods, theinitial ‘soup’ of adenovirus sample in PrimeStore and lysis/EtOH wascentrifuged through at 600 uL (200 uL sample+400 uL ‘soup’) until allwas passed. The wash steps: 1 and 2 were under normal protocols at 200uL each, with wash 2 twice to ensure efficient purification. The elutionstep was carried out with two hot 25 uL aliquots centrifuged twice toensure maximum yield.

For the bead extractions, the beads were prepared by washing 0.5 mL ofstock Saline beads (Part #: 37002D) three times in nuclease-free waterand re-suspended in 25 mL of PrimeXtract Lysis Buffer. This dilutiongives a final silica bead concentration of 0.8 mg/mL. The Buffer Dformulation+carboxy beads was made by taking 1.0 mL of Stock beads (50mg/mL) and placing it in 50 mL of Buffer D after washing the beads threetimes in TE Buffer. This dilution gives a final carboxy beadconcentration of 1 mg/mL.

For Saline bead only extractions, 300 uL of beads were added to a 1.5 mLlow-bind microcentrifuge tube. 200 uL of serially diluted infusedPrimeStore was added and allowed to vortex/incubate for 5 minutes.PrimeXtract wash 1 and 2 were added in 200 uL amounts with wash 2occurring twice to increase extraction purity. A heated step was addedfor 30 seconds to ensure complete ethanol removal. 50 uL nuclease-freewater (heated) elution was added and allowed to incubate for 1 minute.The elution volume was transferred to a new 1.5 mL microcentrifuge tube.

To each PrimeStore diluted Adenovirus tube (set of 1), 300 uL ofprepared beads (Saline) was added directly to 200 uL of serially dilutedAdenovirus in a low-bind microcentrifuge tube, the solutions wereconstantly vortexed/incubated for 5 minutes. A magnet stand was used tosequester the beads on the side while the liquid volume inside the tubewas aspirated. The beads were resuspended in 200 uL freshly preparedNALC solution (alkaline pH). The slurry beads were incubated for 10minutes then vortexed and allowed to incubate for 5 minutes all at roomtemperature (e.g., ambient temp.). Once complete, the slurry wassequestered by the magnet stand and 600 uL of carboxy beads (GEHealthcare or ReSyn in Buffer D) was added to the remaining volume ofliquid to allow for nucleic acid transfer. The new combination of beadswas vortexed and incubated for 5 minutes.

The beads were sequestered using a magnet stand and the fluid volume wasaspirated using a pipette. Two washes of freshly made 80% EtOH wereadded (500 uL each) and each time aspirated using the magnet stand. Ahair dryer heated step (heat reduces the drying time, but is nototherwise required) was added for 30 seconds to ensure complete ethanolremoval (residual EtOH interferes with PCR) and elution was carried outby adding 50 uL of hot nuclease free water to the beads and incubatingfor 1 minute. Elution volumes were transferred to new 1.5 mL collectiontubes for real-time PCR Adenovirus assay in double repetitions to testfor extraction efficiency.

Briefly, a three-step approach is used as a bead-based extractionsystem. Step 1 involves concentrating a 2.0 mL samples of adenoviruscollected in PrimeStore MTM (across a 10-fold serial dilution). This wasperformed using commercially available silica coated beads (LifeTechnologies). The beads are magnetized so concentration was performedwith a magnet and the liquid volume (in this case PrimeStore MTM(Longhorn Vaccines and Diagnostics, LLC) and lysed cellular debris)removed from the tube. Step 2) An intermediate buffer (e.g.,Tris-HCl/NaOH, saline, dilute alkaline, TE buffer, and/or NALC) wasadded to the sample with a basic pH as a compatible matrix for theaddition of magnetized carboxy beads. This intermediate buffer alsoemulsifies difficult specimens such as sputum, nasal discharge, tissues,etc. which can create a slime-like coating on the beads. The solutionprevents the beads from clumping and further chews up difficult samples.Step 3) carboxy beads in Buffer D were added to the tubes. Buffer D doesnot contain chaotrophic agents (e.g., guanidine) or denaturing agents,but contains PEG (polyethylene glycol and NaCl) to effectivelyprecipitate and dehydrolyze nucleic acids; plus additional surfactants(e.g., Tween-20, Triton-X) and ethanol that promote further processing(lysing, degradation of non-nucleic acid polymers) of cells and cellulardebris. As shown in FIG. 6, superior detection was noted using thisthree-step approach compared to commercial extraction using silica spincolumns across every dilution. Most surprising, was that at the lowestdilution (adenovirus at 10⁻⁸, about 10 genomic equivalents), spincolumns had a C_(T) value of 40 (no detection) while we showed detectionat a C_(T) value of 35. FIG. 6 demonstrates superior detection, asevidenced by decreased cycle threshold values (C_(T)) during real-timePCR with bead-based extraction (second column, diagonal stripes), ascompared to results obtained using a routine commercial silica columnextraction kit (first column, no stripes).

Example 11 Carboxy Bead Extraction Using Different Sources of Beads

FIG. 7 shows the results of carboxy bead extraction with three differentcompositions of commercially available carboxy beads (all OUT salinebeads, 300 μl plus NALC). Triplicate real-time PCR reactions wereanalyzed over a range of 10⁻³ to 10⁻⁸ using a real-time universalAdenovirus assay. The first column of each set represents the cyclethreshold achieved with carboxy beads obtained from GE (Cardiff, Whales)(RED diagonal stripes with 600 μl GE carboxy. The second and thirdcolumn of each set are Resyn beads (South Africa) at 2% (BLUE no stripeswith 2% 600 μl ReSyn Carboxy) and 5% (GREEN horizontal stripes with 5%600 μl ReSyn Carboxy) respectively. This example illustrates thatdifferent types of carboxy beads provide the similar results. Althoughbeads provided by GE Healthcare had slightly superior performance (lowerCt value), there were little difference between bead brands used.

Example 12 MTB Detection Using Real-Time PrimeMix MTB Multiplex Assay

A comparison of a standard commercial silica column extraction from two10-fold serial reduction ladders of MTB in either PrimeStore MolecularTransport Medium (MTM; Blue, no stripes) or phosphate buffered solution(PBS; Red, diagonal stripes) is shown in FIG. 8. As can be seen, MTBplaced into PrimeStore MTM was more sensitive (based on real-time PCRcycle threshold values) compared to equivalent amounts of MTB in PBS,which is considered a benign matrix. This difference is believed due tothe ability of PrimeStore to completely lyse the phospholipids ofgram-positive bacteria, even the very hardy MTB microbes. At the lowestdilution (0.1 CFU/mL) there was no detection (C_(T)=40) for both MTB inPrimeStore and PBS. However, when MTB was extracted using a bead-basedapproach developed at Longhorn that involves first concentrating 2.0 mLand then extracting using a combination of silica and carboxy beads, thelowest dilution was readily detected (C_(T)=34; Green, horizontalstripes). This is significant because common or routine silica spincolumn extraction methods would not be able to detect pathogen targetfrom low-level samples, particularly from original specimens (sputum,nasal washings, etc.) where loads may be below detection limits. Theability to concentrate and extract using the bead-based approachdescribed herein increases detection/characterization limits usingdownstream molecular methods such as real-time PCR and/ornext-generation sequencing.

Previously this approach was demonstrated for detection of adenovirus.This application uses Mycobacterium tuberculosis, and can be expandedfor use in HIV viral load detection or for detection of influenzaviruses. Furthermore, this chemistry and described methodology involvesmagnets and magnetized nanobeads and can be adapted for use in automatedextraction units such as the Roche MagnaPure, Qiagen M48 and othercommercially available systems.

Example 13

Real-time PCR detection using PrimeMix MTB Complex after concentratingtotal nucleic acids from MTB in PrimeStore MTM (i.e., high, medium andlow concentrations). As shown in FIG. 9, after concentrating 1.0 mL downto −0.1 mL, samples were extracted using: 1) commercial spin column(PrimXtact) extraction (RED, diagonal lines), or 2) Longhorn'sbead-based methodology (GREEN, no lines). According to quantitativereal-time PCR detection of high, medium, and low MTB concentrations spincolumn and bead extraction methods were comparable when processed afteran initial concentration step. However, the Longhorn bead based methodshowed slightly better cycle threshold values at all threeconcentrations. Triplicate averages are shown. After first performingconcentration step using silica beads, one can either continue withextraction using the carboxy bead methodology disclosed herein or aconventional spin column extraction methodology. From the raw dataset,repeated samples show that overall fluorescence was slightly betterusing Longhorn beads compared to silica spin columns (see FIG. 10; high,medium and low refer to FIG. 9 values). This indicates a cleanerpreparation with less carryover of contaminates.

Example 14

The extraction procedure was developed using optimized buffers andchemically coated magnetized beads for concentrating and subsequentlypurifying nucleic acids from samples collected in PS-MTM to enhancequantitative PCR (qPCR) microbial detection.

Ten-fold serial dilutions of influenza A H3N2 (10⁵ to TCID₅₀/ml), andMycobacterium tuberculosis (MTB; 10⁵ to 1 CFU/ml) were prepared inPS-MTM and analyzed using an ABI-7500 instrument. Prior to amplificationtriplicate nucleic acid extractions were performed for each dilutionusing bead-based extraction and compared to commercial extraction usingQiagen QiAmp DNA Mini. An experimental overview of the methodology isshown in FIG. 11.

According to qPCR, bead-based extraction was more sensitive, i.e., lowercycle threshold (C_(T)) values at each dilution for influenza A (seeFIG. 12A), Adenovirus (Type 5) (see FIG. 12B), and Mycobacteriumtuberculosis (see FIG. 12C). At 1 CFU/ml, MTB was detected (avg.C_(T)=35.6; S.E.=1.4) using bead-based extraction, but not detected(C_(T)=40) from extraction using Qiagen. FIG. 13A indicates PCRefficiency with influenza A of 97.2% for bead-based vs. 110% for Qiagen.FIG. 13B indicates a PCR efficiency with Adenovirus (Type 5) of 93% forbead-based vs. 110% for Qiagen. FIG. 13C indicates a PCR efficiency withM. tuberculosis of 96.8 for bead-based vs. 96.8% for Qiagen. Eachextraction was carried out in triplicate and plotted as the average ofthose determinations +/− the standard error. A C_(T) value of 40 is notdetected. Best-fit linear regression, slope and PCR efficiency areindicated. PCR efficiency E=(−1/slope)−1. To summarize, qPCRefficiencies were more improved using bead-based nucleic acid extraction(96.8%-97.2%) as compared to qPCR efficiencies obtained using Qiagenextraction (96.8%-110%). The bead-based approach offers a concentrationfactor to detect low level RNA/DNA. Magnetized beads and optimizedchemistry produce cleaner extraction preparations yielding high purity.This methodology is also important for improving qPCR detection and nextgeneration sequencing of pathogens directly from low target clinicalspecimens.

Other embodiments and uses of the invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof the invention disclosed herein. All references cited herein,including all publications, U.S. and foreign patents and patentapplications, are specifically and entirely incorporated by reference.U.S. Pat. No. 8,084,443 entitled “Biological Specimen Collection andTransport System and Method of Use,” which issued Dec. 27, 2011; U.S.Pat. No. 8,080,645 entitled “Biological Specimen Collection/TransportCompositions and Methods,” which issued Dec. 20, 2012, U.S. Pat. No.8,097,419 entitled “Compositions and Method for Rapid, Real-TimeDetection of Influenza A Virus (H1N1) Swine 2009,” which issued Jan. 17,2012, U.S. patent application Ser. No. 13/094,809 entitled “Compositionsand Method for Detecting, Identifying and QuantitatingMycobacterial-Specific Nucleic Acid,” which was filed Apr. 26, 2011, andInternational Application No. PCT/US2012/35253 entitled “Compositionsand Method for Detecting and Identifying Nucleic Acids in BiologicalSamples,” filed Apr. 26, 2012, are each specifically and entirelyincorporated by reference. The term comprising, where ever used, isintended to include the terms consisting and consisting essentially of.Furthermore, the terms comprising, including, and containing are notintended to be limiting. It is intended that the specification andexamples be considered exemplary only with the true scope and spirit ofthe invention indicated by the following claims.

1. A method of extracting nucleic acids from a biological samplecontaining cells and/or microorganisms comprising: combining thebiological sample with a lysis buffer to form a mix; combining the mixwith magnetic matrix material to form a solution, wherein neither thebuffer or matrix material disrupt the cells and/or microorganisms of thebiological sample and the magnetic matrix material binds to nucleicacids of the biological sample other than those present within the cellsand/or microorganisms; exposing the solution to a magnetic field andremoving liquid to concentrate the magnetic matrix material; adding analkaline buffer to the concentrated magnetic matrix material to form amixture, wherein the alkaline buffer causes the release of nucleic acidsfrom the magnetic matrix material; adding carboxy-modified magneticbeads in a binding buffer to the mixture wherein the carboxy-modifiedmagnetic beads bind to the specific nucleic acid sequences; exposing themixture to a magnetic field and removing liquid to isolate thecarboxy-modified magnetic beads bound to the specific nucleic acidsequences; and eluting the one or more specific nucleic acid sequencesfrom the carboxy-modified magnetic beads using purified water and/or aTris-EDTA buffer.
 2. The method of claim 1, wherein the lysis buffercomprises a chaotrope, a detergent, a reducing agent, a buffer, and achelator at a pH of about 6-8.
 3. The method of claim 1, wherein thebiological sample combined with buffer is stored for between about 2days to about 90 days before combining with magnetic matrix material. 4.The method of claim 3, wherein the biological sample combined withbuffer is stored for between about 2 days to about 20 days beforecombining with magnetic matrix material.
 5. The method of claim 1,wherein the binding buffer comprises PEG, a salt, a buffering agent, achelator, a detergent, NLS and an alcohol.
 6. The method of claim 1,which does not involve centrifugation.
 7. The method of claim 1, whichis performed in a single vessel.
 8. The method of claim 1, which isautomated for high-throughput analysis of a plurality of biologicalsamples.
 9. The method of claim 1, further comprising analyzing thespecific nucleic acid sequences by a PCR.
 10. The method of claim 1,further comprising identifying the specific nucleic acid sequences.